Conventionally, it is widely known, as described, for example, in patent documents 1 to 3, that a disc brake apparatus with a parking mechanism performs braking at the time of running (service brake) by means of hydraulic pressure, and performs braking at the time of parking (parking brake) mechanically. FIGS. 30 and 31 show structures described in the patent document 2. First, the conventional structure is briefly explained. A rotor 1 is rotated together with a vehicle wheel. A support member 2 is fixed to a vehicle body (a component of a suspension system, such as a knuckle) and is near the rotor 1. Inner and outer pads 3 and 4 and a caliper 5 are supported by the support member 2 to be displaceable in an axial direction (in the description and claims, the axial direction, if not specified otherwise, refers to the axial direction of the rotor 1). The caliper 5 is formed by bonding and fixing a main part 6 which forms one part of the caliper 5 from the outer side to the middle, and a subpart 7 which forms the other part of the caliper 5 at the inner side by bolts 8 and 8. A piston 10 is fitted via a sleeve 11 in a cylindrical space 9 which is provided at the anti-rotor side half part of the main part 6 to be displaceable in the axial direction and fluid tightly sealed. An adjusting mechanism 12 and a cam mechanism 13 are provided between the piston 10 and the back end surface of the subpart 7 successively from the piston 10 side.
When the service brake is operated, a hydraulic pressure is applied in the cylindrical space 9 (pressurized brake oil is sent inside), the piston 10 is displaced in a direction of approaching the rotor 1, and the inner pad 3 is pressed against the inner side surface of the rotor 1. Due to a reaction of the pressing, the caliper 5 is displaced to the inner side relative to the support member 2, and the outer pad 4 is pressed against the outer side surface of the rotor 1 by a caliper claw 14 which is formed at the outer side end of the caliper 5. As a result, the rotor 1 is strongly pressed from both sides in the axial direction so that a braking is performed.
When the parking brake is operated, a cam shaft 16 which forms a cam mechanism 13 is rotated by a parking lever 15. Then, based on this rotation, the engagement of rollers 17 and 17 and cam surfaces 18a and 18b changes so that the distance between a pair of cam members 19a and 19b is expanded and an adjusting spindle 20 is pressed in the direction of approaching the rotor 1. Then, the adjusting spindle 20 presses the piston 10 in a direction of approaching the rotor 1 via an adjusting screw 21. As a result, similarly to the service brake mentioned above, the rotor 1 is held from both sides in the axial direction by the inner and outer pads 3 and 4 so that a braking is performed.
When the wear of linings which form the two pads 3 and 4 develops, the adjusting screw 21 will be rotated and displaced in the direction of approaching the rotor 1 relative to the adjusting spindle 20 at the time of the service brake. When the service brake is released, the retreated location of the piston 10 moves to the rotor 1 side, and the wear of the linings which form the two pads 3 and 4 is compensated. If an excessive brake fluid pressure is applied to the piston 10 when the service brake is operated, for example, in a sudden braking, the adjusting screw 21 becomes unable to be rotated relative to the adjusting spindle 20, the adjusting spindle 20 resists the resilientity of a spring 22, and moves in the direction of approaching the rotor 1 together with the adjusting screw 21. Thus, a so-called over adjustment, which makes the piston 10 to be displaced in the direction of approaching the rotor 1 so that the linings which form the two pads 3 and 4 rub against both side surfaces of the rotor 1 at the time of un-braking, is prevented.
It is clear from FIG. 31 that the above disc brake apparatus with the parking mechanism has many small components, and the assembly operation is troublesome. For the conventional structure shown in FIGS. 30 and 31, since the caliper 5 is divided as the main part 6 and the subpart 7, after many of the components which form the parking mechanism among the components of the caliper 5 are attached to the subpart 7, the assembly operation can be performed comparatively easily by combining the subpart 7 and the main part 6 with the bolts 8 and 8. However, it is disadvantageous to use a two-piece type caliper if the size and weight of the disc brake apparatus with the parking mechanism including the caliper are to be reduced. In order to reduce the size and the weight of the disc brake apparatus with the parking mechanism, it is preferred to use an integrated caliper like the structure of the invention described in the patent documents 1 and 3. However, in this case, it is necessary to consider facilitating the operation of assembling the small components which form the adjusting mechanism into the back end (anti-rotor side end) of the cylindrical space provided in the caliper.
Although an assembly technique is described in the patent document 1 in which after the components have been incorporated in the inner part of the cylindrical space, a snap ring for locking is suitably used in assembling, it is not avoided that the assembly operation becomes troublesome. On the other hand, a technique is described in the patent document 3 (the paragraph [0027] of the description and FIGS. 1 and 5), in which components of the parking mechanism which make a thrust to be generated due to a mechanical structure are packed as a sub-assembly unit by a cartridge (31) and a spring retainer (27), and are kept in the cylindrical space. However, for the structure of the invention described in the patent document 3, when the sub-assembly unit is assembled outside the cylindrical space, since the cartridge (31) and some components (inclined element 12) are combined while a part of the cartridge (31) is bended (forming a reshaped lug 32), the combination operation becomes troublesome. In addition, for the structure of the invention described in the patent document 3, when the sub-assembly unit which is assembled beforehand outside is pushed into the cylindrical space of the caliper, it is likely that a protrusion lug (28) of the spring retainer (27) rubs against the inner peripheral surface of the cylindrical space (bore 4). When the inner peripheral surface of the cylindrical space is rubbed, the inner peripheral surface of the cylindrical space may be damaged.